The present invention relates to a process for producing a tolylthiourea. Tolylthiourea are useful as intermediates for dyes and agricultural chemicals. Various processes for production of the same compounds have been proposed. Thus, it has been difficult to produce the same compounds having high purity in a simple industrial process with low cost. The following process have been proposed.
(1) A process using chlorobenzene as a solvent as disclosed in Org. Synth. Coll., Vol. 3, p. 76. PA1 (2) A process using an alcohol as a solvent as disclosed in Japanese Examined Patent Publication No. 17255/1974. PA1 (3) A process using an aqueous solvent as disclosed in Japanese Unexamined Patent Publication No. 148749/1979.
According to the experiments of these processes by the inventors, a production of a by-product of ditolylthiourea has been too much in these processes. The by-product is not easily separated from the product of tolylthiourea to contaminate the product and to give the product having relatively low purity. Even though a crude yield is more than 90% as the process (3), the yeild of the purified product is only up to 80%. In these processes, the yield is also disadvantageously low.